# AD 46-23-01: Muffler Replacement

- Type: Airworthiness directive
- Status: Current
- Products: Univair 415-C, 415-CD and 415-D
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 1,005 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9BB6F0BE3CD5296D86256A4D005D9E2C.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/46-23-01

## The airworthiness directive

46-23-01 ERCO: (Was Mandatory Note 4 of AD-718-6.) Applies Only to 415-C, -CD and -D Aircraft Serial Numbers 113 to 362, Inclusive. To be accomplished within next 50 hours of operation. Trouble in service has indicated the necessity for replacing the original muffler on the serial numbers listed above with a new muffler, Erco P/N 145-40517. (Erco Service Department Memorandum No. 7 dated February 1, 1946, covers this same subject.)

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-718](https://openairdocs.org/tcds/A-718): Univair Aircraft Corporation; names 2 of 2 models: 415-CD, 415-C
- [TCDS A-787](https://openairdocs.org/tcds/A-787): Univair Aircraft Corporation; names 1 of 8 models: 415-D

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 1,005 (1,005 by airframe model, 0 by engine model)
- Makers: Ercoupe 772, Engineering & Research 200, Forney 20, Erco 12, Univair 1

Models with the most aircraft:

- [Ercoupe 415-C](https://openairdocs.org/model/ercoupe-415-c): 623 aircraft (airframe model)
- [Engineering & Research 415-C](https://openairdocs.org/model/engineering-research-415-c): 160 aircraft (airframe model)
- [Ercoupe 415-D](https://openairdocs.org/model/ercoupe-415-d): 101 aircraft (airframe model)
- [Ercoupe 415-CD](https://openairdocs.org/model/ercoupe-415-cd): 48 aircraft (airframe model)
- [Engineering & Research 415-D](https://openairdocs.org/model/engineering-research-415-d): 24 aircraft (airframe model)
- [Forney 415-C](https://openairdocs.org/model/forney-415-c): 17 aircraft (airframe model)
- [Engineering & Research 415-CD](https://openairdocs.org/model/engineering-research-415-cd): 16 aircraft (airframe model)
- [Erco 415-C](https://openairdocs.org/model/erco-415-c): 7 aircraft (airframe model)
- [Erco 415-D](https://openairdocs.org/model/erco-415-d): 4 aircraft (airframe model)
- [Forney 415-D](https://openairdocs.org/model/forney-415-d): 2 aircraft (airframe model)
- [Forney 415-CD](https://openairdocs.org/model/forney-415-cd): 1 aircraft (airframe model)
- [Erco 415-CD](https://openairdocs.org/model/erco-415-cd): 1 aircraft (airframe model)
- [Univair 415-D](https://openairdocs.org/model/univair-415-d): 1 aircraft (airframe model)

All 13 models: https://openairdocs.org/ad/46-23-01/models.md
Every aircraft: https://openairdocs.org/ad/46-23-01/aircraft.md

Its text cites no advisory circulars or STCs.

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